Many trailers do not tip up to a high enough angle for easy discharge of sticky materials such as wet clay. It is, however, possible to arrange for a trailer to tip up to a very high angle, say 80.degree. to 85.degree. from horizontal, and one way of doing this is described in my copending application Ser. No. 522,218, now U.S. Pat. No. 3,963,274, although other ways may be adopted. However, when the trailer is tipped to such a high angle, there is a possibility that it may not readily come down again on the conclusion of the tipping operation because the weight of the trailer body tends to come behind the vertical line through the hinge point of the body and the trailer may be in a situation such that it is just beginning to overbalance backwards.
The object of this invention is to provide means whereby the trailer will come back more readily to its normal horizontal position.
According to this invention there is provided a tip-up trailer having a hydraulic cylinder the interior of which is divided into two compartments by a piston working therein to operate a ram, the first compartment on one side of the piston being filled with fluid to operate the ram, the second compartment on the other side of the piston being closed to the atmosphere and containing a quantity of air or other gas which is compressed and expanded with the movement of the piston. The Second compartment may be connected to a closed storage chamber also filled with air or gas.